Ribbon spool tensioning means



May 22, 1951 w. H. REID RIBBON spoon mxsxoumc means Filed Oct. 29, 1948 INVENTOR. MAE) /7/RM/4N 25/0 i, Arron/MY Patented May 22, 1951 UNITED STATES PATENT OFFICE RIBBON SPOOL TENSIONING MEANS Application October 29, 1948, Serial No. 57,183

4 Claims.

The present invention relates to tensioning devices for ribbon spools for use particularly upon typewriter attachments wherein an inked ribbon is used to make multiple copies.

The invention is shown as applied to a typewriter attachment of the above indicated character as set forth in the patent application of Charles Gordon Rice, Serial No. 41,194, filed July In devices of this type wherein the supplemental ribbon for making the multiple copies is wound upon a spool which is positively driven in one direction and unwound from another or free spool, it is important that the free spool shall not overrun as the ribbon is being unwound therefrom; and this same consideration applies when the drive is reversed to reverse the direction of the ribbon movement. At the same time, the tensioning must not be such as to impose an undue load on the ribbon drive.

The principal object of my invention is toprovide a tensioning means which is certain in its operation and is convenient, easy and economical to assemble in manufacture of the attachment.

Other objects of my invention will be apparent from a consideration of this specification taken in conjunction with the accompanying drawings, in which- Fig. 1 is a vertical section through one arm of the typewriter attachment and the ribbon spool mounted thereon, illustrating my invention;

Fig. 2 is an end View of the ribbon spool drive shaft, looking at the right hand end in Fig. 1, and with the drum removed;

Fig. 3 is an end View of the drive shaft without the tensioning means applied thereto; and

Fig. 4 is a perspective view of a modified form of mounting for the tensioning means.

Referring to Figs. 1 and 3, H indicates a portion of the pivoted arm of the attachment which carries the spool, in this case, adjacent the forward end thereof, it being understood that in such attachments there are two such arms, each carrying a ribbon spool. Since, insofar as the present invention is concerned, the same construction is applied to both spools, it is only necessary to describe one in detail.

A spool spindle bearing 12 is fixed in the arm and rotatably receives the shaft iii of the spool spindle. This spindle carries at the outer (left hand in Fig. 1) end a driving gear, not shown, which is adapted to be suitably driven in the operation of the attachment when the associated spool is the take up spool; and the drive is disconnected so that the associated spool will be free when the opposite spool is being driven to take up the ribbon. A retaining washer I4 is received in a groove in the shaft 13 and cooperates with a thrust washer IS in retaining the shaft in place in the bearing l2. This bearing has a flange l6 fitting against the inner face of the arm II, and an inwardly projecting hub portion [1 which terminates at its inward end in a tapered portion Ill.

The spool spindle also has an enlarged head 2| from which there is an outwardly extending key portion 22. As seen in Figs. 2 and 3, this key portion is desirably angularly shaped to fit a similarly shaped aperture in a driving drum 23. This driving drum is secured in place on the spool spindle by means of a retaining screw 24. The drum 23 is shaped so as to enclose an enlarged head 2! and associated parts of the mechanism, and the sides of the drum receive a ribbon spool 25. Any suitable driving connection may be provided between the drum and the ribbon spool, so that the two rotate in unison. A frictional driving connection is shown in the above identified Rice application.

As seen in Fig. 3, one portion of the periphery of the enlarged head 2| is provided with a narrow, fiat groove 3! which groove receives a flat spring 32. This spring is of greater length than the enlarged head, and may be held in place thereon by a screw 33 engaging in a tapped hole in the head. As will be seen from Fig. 1, the relationship of the tapered portion I8 of the fixed bearing l2 and the enlarged head 2! is such that the grooved portion 3! rotates slightly within the smallest diameter of the tapered portion I8, and that part of the spring 32 which projects beyond the head 2| rides on the tapered portion [8 and because of its relationship is offset to exert a braking tension or drag on the rotation of the spool spindle, and with it the ribbon spool connected thereto.

It will be appreciated that the parts described above are simple to manufacture and that the assembly and tensioning of the spring 32 in the manufacture of the attachment is easily accomplished. Furthermore, the tempering of the spring is not critical.

Fig. 4 illustrates a modified construction in which the enlarged head 2iA of the spool spindle has one portion of the periphery thereof provided with a groove 4!. In this case the groove is mortise shaped, and the sides of the spring 32 may or may not be beveled to form a dovetail to fit with the sides of the mortise groove. The

assembly of the spring is accomplished merely by inserting the spring in the groove, and the tensioning by the outward bending of the tension ing end of the spring together with the mortised groove, provides sufficient friction to hold the spring against dropping out or shifting position as the spindle is rotated. Furthermore, a rough adjustment of the spring tensioning can be had by varying the length of the mortise 41 on the end adjacent the bearing I8, as indicated by the dotted lines 42, thereby providing different angles for the displacement of the end of the spring in its engagement with the tapered portion of the bearing.

While I have shown and described certain preferred embodiments of my invention, it will be understood that modifications and changes may be made therein without departing from the spirit and scope of my invention.

1. A ribbon spool drive comprising a support, a bearing mounted therein and having a, reduced tapered hub portion at one side thereof, a shaft rotatable in said bearing and having an enlarged I a bearing mounted therein, a shaft rotatable in said bearing and having an enlarged head at one side of said bearing, a fiat groove in the periphery of said head, and a flat spring secured in said groove and having an end projecting beyond the head and displaced into engagement with said bearing so as to exert a braking tension upon the rotation of said shaft.

3. A ribbon spool drive comprising a support, a bearing mounted therein, a shaft rotatable in said bearing and having a portion projecting therebeyond, a groove in the projecting portion of the shaft, and a spring mounted in said groove and having a projecting portion frictionally engaging the bearing so as to exert a braking tension on the rotation of the shaft.

4. A ribbon spool drive comprising a support,

1 a bearing therein, a shaft rotatable in said bearing and having a portion projecting beyond the bearing, a mortise groove in said projecting portion, and a flat spring fitting in said groove and having a portion projecting into frictional engagement with the bearing so as to exert a braking effect on the rotation of the shaft. 7

WILEY HERMAN REID.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,227,09 i Uebelmesser May 22, 1917 2,456,660 Werner Dec. 21, 1948 

